1. Field of the Invention
The present disclosure relates to bushings, and more particularly to bushings such as in variable vane systems.
2. Description of Related Art
Traditionally, a turbo fan engine for an aircraft includes multiple stages of variable vanes to condition and guide airflow through the compressor and/or turbine sections. Variable vanes are configured to be pivoted about their vane axis in order to optimize airflow characteristics for various operating conditions.
It is known that variable vanes can be connected to a synchronization ring (sync ring), each by a respective vane arm connected to the stem of the vane. The sync ring can drive each vane counter-clockwise and/or clockwise around its respective longitudinal axis in order to set the optimal vane stage angle for a particular operating condition. Each vane stem is surrounded by a respective bushing and each bushing is operatively connected to a cylindrical case. The vane stems rub against the bushing inner surface and can cause wear at the interface. Material degradation, engine vibration and bearing stress can further induce bearing wear, such as surface galling, erosion, fretting, and the like. Eventually, the bearing wear can necessitate maintenance and/or replacement of worn components.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for bushings that allow for improved durability and wear resistance. The present disclosure provides a solution for these problems.